Making red azo dye lakes.



UNITED .sT Tns rn ENT OFFICE-.-

OTTO ERNST AND CARL PRETZELL, OF HCCH ST-ON-THE-M AI N, GERMANY, ASSIGNORS TO FARBWERKE VORM. MEISTER LUCIUS & BRUNING, OF HOCHST-ON-THE-MAIN, GERMANY,

A CORPORATION OF GERMANY.

MAKING RE D AZ O DYE LAKES.

Specification of Letters Patent.

Application filed. April 11, 1907.

To all whom it may concern:

Be it known that we, OTTo ERNST, Ph. D., and CARL PRETZELL, Ph. D., chemists, citizens of the German Empire, and residing at Hochst-on-the-Main, Germany, have invented certain new and useful Improvements in Making Red Azo Dye Lakes, of which the following is a specification.

The dyestufl' obtained by combinin diazotized ortho-nitranilin with 2-naphth0 0-sulfonic acid has not hitherto been used for the technical manufacture of body colors. We have found that this dyestuff is specially suited for this )urpose and yields body colors of commercially valuable properties.

The dyestuff is applied to a substratum in a suitable manner, orange-red to scarletcolored products being obtained which are advantageously distinguished by their clear tints and excellent fastness to light, sufficing to fulfil the highest demands in this respect, particularly as compared with the lakes obtained from the ordinary acid azo-orange dyestuffs.

The dyestuff used according to this invention is also superior to the azo-orange dyestuffs with respect to their being readily precipitated as metallic salts.

. The body colors may be obtained, for instance, as follows Example: 100 kilos of finely ground heavy spar are well stirred with a suitable proportlon of water, say 100 kilos and a solution of 5 kilos of the sodium salt of the dyestuif from ortho-nitrodiazobenzene and 2-naphthol-fi-monosulfonic acid is added. A solution of 6 kilos of anhydrous calcium chlorid is then allowed to run in while stirring well and the whole is heated to ebullition. The

pigment is then dried and used as a painting co or. v

The manufacture of the dyestufl" and body colors may also occur in a single operation, for instance, as follows A diazo solution obtained in the known manner from 13.8 kilos of ortho-nitranilin. 34 kilos of hydrochloric acid of 20 B. specific gravity and 6.9 kilos of sodium nitrite 1s run into a solution of 24.8 kilos of sodium.

2-naphthol-6-sulfonate and 23 kilos of caustic soda-lye of 40 B. specific gravity, in a suitable proportion of water, say 1,000 kilos. There is then added a solution-of 4 kilos of crystallized barium chlorid and the whole is boiled. When cold, a washed hydrated alumina-blanc-fixe paste obtained in the usual manner from 100 kilos of aluminum sulfate, 50 kilos of sodium carbonate and 70 kilos of barium chlorid is stirred in; the lake is then filtered, pressed and dried. A printing color is thus obtained of very great fastness to light.

' Having now described our invention, what we claim is As new products, the body-colors derived from the azo dyestufi resultingv from diazotized ortho-nitranilin and naphtholsulfonic acid2 :6, being brilliant orange-red to scarlet colored powders insoluble in water and oil and,exceedingly fast to li ht.

In testimony, that we 0 aim the foregoing as our invention, we have signed our names in presence of two subscribin witnesses.

OTTO TIRNST, CARL PRETZELL. Witnesses:

JEAN GRUND, CARL GRUND. 

